WASHINGTON — The vice presidency historically has been a golden ticket to a presidential nomination.

Whether that ticket works for Vice President Joe Biden in 2016 depends to a great extent on the baggage he may be carrying.

Biden's age (he turns 70 on Nov. 20), his tendency toward verbal gaffes, the success or failure of President Obama's second term and whether Secretary of State Hillary Rodham Clinton decides to make a White House run all will influence Biden's chances in 2016.

Biden also has 40 years of experience in politics and plenty of IOUs from well-connected Democrats. And he has the next four years to carve out high-profile special projects.

"It's a long way to 2016, but Vice President Biden would be the favorite right now," said Joel K. Goldstein, a law professor at Saint Louis University and an expert on the vice presidency.

The last sitting vice president to be denied his party's nomination was Democrat Alben Barkley, who served with President Harry Truman from 1949-1953. Barkley tried for the Democratic presidential nomination in 1952, but party bosses chose Adlai Stevenson instead.

On Tuesday, Biden offered a few winking references to a possible 2016 White House bid. At one stop, he said he didn't think this year would mark the last time he voted for himself. At another he joked, "Oh, I'm going to go back home and run for county council or something."

"His office is 45 feet from the Oval Office and he's probably going to say, 'I could do the job as well. And I want it,'" said former Republican Vice President Dan Quayle, now head of a private investment firm.

Biden also told KLUC radio in Las Vegas, "Aww hell, 2016 is a lifetime away." His office declined comment beyond Biden's remarks to the radio station.

Former U.S. Sen. Ted Kaufman, Biden's chief of staff for 19 years, said Biden will sit down with family to decide.

"He hasn't spent a lot of time thinking about it," Kaufman said.

On Election Day 2016, Biden will be a few weeks away from his 74th birthday — which will make him slightly older than two other presidential nominees — Republicans Bob Dole and John McCain — were in 1996 and 2008. Biden also will be older than Ronald Reagan was during his 1984 re-election campaign.

Kaufman said Biden is in good shape and energetic, and just survived a grueling campaign.

But GOP consultant Ed Goeas said he will be too old to be considered a viable presidential contender.

"And there are too many young and upcoming Democrats who would have something to say about it, not to mention Hillary Clinton," said Goeas, president of The Tarrance Group. Clinton is five years younger than Biden.

Goeas also said Biden would have to get past his image as "crazy Uncle Joe," a reputation built on his history of verbal gaffes.

In August, for instance, Biden told a crowd in Virginia that GOP presidential nominee Mitt Romney's regulatory policies would "put y'all back in chains," a comment the Romney campaign described as "a new low" for the Obama-Biden ticket.

Quayle, who also drew attention for verbal missteps, noted that, "When you run for president, you'll be under the microscope even more."

Goldstein agreed that Biden's rhetorical slips are an issue.

"He was a very significant legislator who chaired two (Senate) committees and was respected by people across the aisle," Goldstein noted. "As vice president he has been enormously influential and successful and yet because of what are perceived as gaffes, sometimes he doesn't get his full due in being perceived as a significant figure."

But Bruce Oppenheimer, political science professor at Vanderbilt University, said voters have accepted that part of Biden.

"He's the friend you have who has some flaws, but he's been a friend so long you accept the flaws," Oppenheimer said.

The Obama administration's record over the next four years also will play into Biden's consideration of a possible White House run.

"It can be a challenge to step out from under the shadow of the president you've served under," said Doug Hattaway, a top aide to Gore during his 2000 presidential campaign. "You own the successes and failures of your administration, so there's a hefty record to answer for — for better or worse."

Gore ran in 2000 with the memory of his boss' sex scandal still fresh in the public's mind. Humphrey's presidential run was tainted by his association with the Vietnam War. Mondale's bid was hampered by the high inflation and rising interest rates of the last two years of the Carter administration.

"For him to be successful as a presidential candidate, first of all the administration has to be successful," Goldstein said of Biden.

Some factors that will affect Biden's decision on whether to run — such as Hillary Clinton's ambitions and how the economy performs — are outside his direct control. But experts say the vice presidency offers Biden chances to prove his leadership.

If both Clinton and Biden run, Obama would be in the difficult position of having to choose between his second-in-command and the woman who served as secretary of state — and whose husband provided significant help to Obama's 2012 campaign.

"If she says she's going to step up, I think Joe Biden will step back," said James Magee, political science professor at the University of Delaware.

A new survey shows Clinton would start out as a dominant favorite in the 2016 Iowa caucuses if she chooses to run for president, Politico reported on Thursday.

The survey, conducted by Public Policy Polling, showed Clinton taking 58% of the Iowa vote in a hypothetical presidential run. Biden trailed far behind at 17%. If Clinton doesn't run, Biden would jump into the lead with 40% of the vote, Politico reported.

Magee said Biden needs to find projects to work on as vice president that will bring him credit, such as bridging the partisan divide in Washington.

"This is something the American people are so disgusted with," Magee said. "If Biden can bring some sense to divided government — in which things get done — that would be tremendous. He's got to be able to take credit for something."

Kaufman said Biden is well-positioned to persuade key Republicans and Democrats to work together on the economy and other issues. During his 36 years in the Senate, he worked effectively across the aisle and even spoke at the funerals of conservative Republican Sens. Strom Thurmond of South Carolina and Jesse Helms of North Carolina.

The most challenging bipartisan project in the near term will be working out a deal to stave off the "fiscal cliff" of tax hikes and spending cuts set to go into effect next year, and to reach broader agreement on reducing the deficit.

But playing a major role there could be a minefield, Oppenheimer said. Finding common ground with Republicans would require compromises that many Democrats would find unacceptable.

"If you're out in front and it makes people unhappy, you get the blame," Oppenheimer said. "But if you're not in front, it's hard to say you're important and should be viable as a presidential candidate."

Biden said earlier this week he expects to play a key role in debt talks and to continue conducting foreign policy missions and working with lawmakers.

"It'll be whatever the issue of the day is," he said aboard Air Force Two after the election. "Like I told (the president) the first time, I only want those assignments that have a sell-by date, you know?"

In his radio interview with KLUC in Las Vegas, Biden sounded buoyed by the possibility of breaking through gridlock — and keen on running for president.

"I've got significant responsibility and I'm looking forward to getting an agenda passed in the Congress, because I think the fever is going to break here," he said. "I think the Republican Party is going to be taken back by the mainstream ... of their party. And I think we're going to be able to work together. And I'm looking forward to that."